craigslist - craigslist provides local classifieds and forums for jobs, housing, for sale, services, local community, and events
Inside Real Estate - A must-read for those who buy, sell, and develop real estate
classified-ads - Classified Ads is a web based free to use ad viewing and posting system that can be accessed from any part of the world to view the local ads of any area and location.
Hutsy - Make an all cash offer on your next home
Gumtree - Gumtree is the first site for free classifieds ads in the UK. Buy and sell items, cars, properties, and find or offer jobs in your area.
ZeroDown - The easiest transition from renting to homeownership